Many electronic devices include one or more rechargeable batteries that require external power to recharge from time to time. Often, these devices may be charged using a similar power cord or connector, for example a universal serial bus (“USB”) connector. However, despite having common connection types, devices often require separate power supplies with different power outputs. These multiple power supplies can be burdensome to use, store, and transport from place to place. As a result, the benefits of device portability may be substantially limited.
Furthermore, charging cords may be unsafe to use in certain circumstances. For example, a driver of a vehicle may become distracted attempting to plug an electronic device into a vehicle charger. In another example, a charging cord may present a tripping hazard if left unattended.
To account for these and other shortcomings of portable electronic devices, some devices include an inductive charging device. The user may simply place the electronic device on a charging surface of the inductive charging device to transfer energy from the charging device to the electronic device. The charging device transfers energy to the electronic device through inductively coupling between a transmitter coil in the charging device and a receiver coil in the electronic device. Unfortunately, inductive charging can be adversely affected by power losses, which reduce the efficiency of the energy transfer. The conversion of energy into heat during the energy transfer process contributes to the power losses.
Additionally, the performance of other devices or functions in the electronic device may be adversely impacted while energy is transferring inductively from the charging device to the electronic device. As one example, an electronic device can include a touch sensing device. During inductive energy transfer, the touch sensing device may not be able to detect a touch on an input surface because the amount of noise transferred to the electronic device during the inductive energy transfer may overwhelm the signal used to determine or sense touch.